scholarly journals Inhibition of LC3-associated phagocytosis in COPD and in response to cigarette smoke

2021 ◽  
Vol 15 ◽  
pp. 175346662110397
Author(s):  
Patrick F. Asare ◽  
Hai B. Tran ◽  
Plinio R. Hurtado ◽  
Griffith B. Perkins ◽  
Phan Nguyen ◽  
...  

Introduction/Rationale: In chronic obstructive pulmonary disease (COPD), defective macrophage phagocytic clearance of cells undergoing apoptosis by efferocytosis may lead to secondary necrosis of the uncleared cells and contribute to airway inflammation. The precise mechanisms for this phenomenon remain unknown. LC3-associated phagocytosis (LAP) is indispensable for effective efferocytosis. We hypothesized that cigarette smoke inhibits the regulators of LAP pathway, potentially contributing to the chronic airways inflammation associated with COPD. Methods: Bronchoalveolar (BAL)-derived alveolar macrophages, lung tissue macrophages obtained from lung resection surgery, and monocyte-derived macrophages (MDM) were prepared from COPD patients and control participants. Lung/airway samples from mice chronically exposed to cigarette smoke were also investigated. Differentiated THP-1 cells were exposed to cigarette smoke extract (CSE). The LAP pathway including Rubicon, as an essential regulator of LAP, efferocytosis and inflammation was examined using western blot, ELISA, flow cytometry, and/or immunofluorescence. Results: Rubicon was significantly depleted in COPD alveolar macrophages compared with non-COPD control macrophages. Rubicon protein in alveolar macrophages of cigarette smoke-exposed mice and cigarette smoke-exposed MDM and THP-1 was decreased with a concomitant impairment of efferocytosis. We also noted increased expression of LC3 which is critical for LAP pathway in COPD and THP-1 macrophages. Furthermore, THP-1 macrophages exposed to cigarette smoke extract exhibited higher levels of other key components of LAP pathway including Atg5 and TIM-4. There was a strong positive correlation between Rubicon protein expression and efferocytosis. Conclusion: LAP is a requisite for effective efferocytosis and an appropriate inflammatory response, which is impaired by Rubicon deficiency. Our findings suggest dysregulated LAP due to reduced Rubicon as a result of CSE exposure. This phenomenon could lead to a failure of macrophages to effectively process phagosomes containing apoptotic cells during efferocytosis. Restoring Rubicon protein expression has unrecognized therapeutic potential in the context of disease-related modifications caused by exposure to cigarette smoke.

2020 ◽  
Author(s):  
Hai B Tran ◽  
Rhys Hamon ◽  
Hubertus Jersmann ◽  
Miranda P Ween ◽  
Patrick Asare ◽  
...  

Abstract IntroductionThe role inflammasomes play in chronic obstructive pulmonary disease (COPD) is unclear. We hypothesised that the AIM2 inflammasome is activated in the airways of COPD patients, and in response to cigarette smoke.Methods Lung tissue, bronchoscopy-derived alveolar macrophages and bronchial epithelial cells from COPD patients and healthy donors; lungs from cigarette smoke-exposed mice; and cigarette smoke extract-stimulated alveolar macrophages from healthy controls and HBEC30KT cell line were investigated. AIM2 inflammasome activation was assessed by multi-fluorescence quantitative confocal microscopy of speck foci positive for AIM2, inflammasome component ASC and cleaved IL-1β. Subcellular AIM2 localization was assessed by confocal microscopy, and immunoblot of fractionated cell lysates. Nuclear localization was supported by in-silico analysis of nuclear localization predicted scores of peptide sequences. Nuclear and cytoplasmic AIM2 was demonstrated by immunoblot in both cellular fractions from HBEC30KT cells.Results Increased cytoplasmic AIM2 speck foci, colocalized with cleaved IL-1β, were demonstrated in COPD lungs (n=9) vs. control (n=5), showing significant positive correlations with GOLD stages. AIM2 nuclear-to-cytoplasmic redistribution was demonstrated in bronchiolar epithelium in cigarette-exposed mice and in HBEC30KT cells post 24 hrs stimulation with 5% cigarette smoke extract. Alveolar macrophages from 8 healthy non-smokers responded to cigarette smoke extract with an >8-fold increase (p<0.05) of cytoplasmic AIM2 and >6-fold increase (p<0.01) of colocalized cleaved IL-1β speck foci, which were also localized with ASC.Conclusion The AIM2 inflammasome is activated in the airway of COPD patients, and in response to cigarette smoke exposure, associated with a nuclear to cytoplasmic shift in the distribution of AIM2.


2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Hai B. Tran ◽  
Rhys Hamon ◽  
Hubertus Jersmann ◽  
Miranda P. Ween ◽  
Patrick Asare ◽  
...  

Abstract Introduction The role inflammasomes play in chronic obstructive pulmonary disease (COPD) is unclear. We hypothesised that the AIM2 inflammasome is activated in the airways of COPD patients, and in response to cigarette smoke. Methods Lung tissue, bronchoscopy-derived alveolar macrophages and bronchial epithelial cells from COPD patients and healthy donors; lungs from cigarette smoke-exposed mice; and cigarette smoke extract-stimulated alveolar macrophages from healthy controls and HBEC30KT cell line were investigated. AIM2 inflammasome activation was assessed by multi-fluorescence quantitative confocal microscopy of speck foci positive for AIM2, inflammasome component ASC and cleaved IL-1β. Subcellular AIM2 localization was assessed by confocal microscopy, and immunoblot of fractionated cell lysates. Nuclear localization was supported by in-silico analysis of nuclear localization predicted scores of peptide sequences. Nuclear and cytoplasmic AIM2 was demonstrated by immunoblot in both cellular fractions from HBEC30KT cells. Results Increased cytoplasmic AIM2 speck foci, colocalized with cleaved IL-1β, were demonstrated in COPD lungs (n = 9) vs. control (n = 5), showing significant positive correlations with GOLD stages. AIM2 nuclear-to-cytoplasmic redistribution was demonstrated in bronchiolar epithelium in cigarette-exposed mice and in HBEC30KT cells post 24 h stimulation with 5% cigarette smoke extract. Alveolar macrophages from 8 healthy non-smokers responded to cigarette smoke extract with an > 8-fold increase (p < 0.05) of cytoplasmic AIM2 and > 6-fold increase (p < 0.01) of colocalized cleaved IL-1β speck foci, which were also localized with ASC. Conclusion The AIM2 inflammasome is activated in the airway of COPD patients, and in response to cigarette smoke exposure, associated with a nuclear to cytoplasmic shift in the distribution of AIM2.


2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Daisuke Morichika ◽  
Akihiko Taniguchi ◽  
Naohiro Oda ◽  
Utako Fujii ◽  
Satoru Senoo ◽  
...  

Abstract Background IL-33, which is known to induce type 2 immune responses via group 2 innate lymphoid cells, has been reported to contribute to neutrophilic airway inflammation in chronic obstructive pulmonary disease. However, its role in the pathogenesis of emphysema remains unclear. Methods We determined the role of interleukin (IL)-33 in the development of emphysema using porcine pancreas elastase (PPE) and cigarette smoke extract (CSE) in mice. First, IL-33−/− mice and wild-type (WT) mice were given PPE intratracheally. The numbers of inflammatory cells, and the levels of cytokines and chemokines in the bronchoalveolar lavage (BAL) fluid and lung homogenates, were analyzed; quantitative morphometry of lung sections was also performed. Second, mice received CSE by intratracheal instillation. Quantitative morphometry of lung sections was then performed again. Results Intratracheal instillation of PPE induced emphysematous changes and increased IL-33 levels in the lungs. Compared to WT mice, IL-33−/− mice showed significantly greater PPE-induced emphysematous changes. No differences were observed between IL-33−/− and WT mice in the numbers of macrophages or neutrophils in BAL fluid. The levels of hepatocyte growth factor were lower in the BAL fluid of PPE-treated IL-33−/− mice than WT mice. IL-33−/− mice also showed significantly greater emphysematous changes in the lungs, compared to WT mice, following intratracheal instillation of CSE. Conclusion These observations suggest that loss of IL-33 promotes the development of emphysema and may be potentially harmful to patients with COPD.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Ying Liu ◽  
Jiawei Xu ◽  
Tian Liu ◽  
Jinxiang Wu ◽  
Jiping Zhao ◽  
...  

Abstract Background Cigarette smoke (CS) is a major risk factor for Chronic Obstructive Pulmonary Disease (COPD). Follistatin-like protein 1 (FSTL1), a critical factor during embryogenesis particularly in respiratory lung development, is a novel mediator related to inflammation and tissue remodeling. We tried to investigate the role of FSTL1 in CS-induced autophagy dysregulation, airway inflammation and remodeling. Methods Serum and lung specimens were obtained from COPD patients and controls. Adult female wild-type (WT) mice, FSTL1± mice and FSTL1flox/+ mice were exposed to room air or chronic CS. Additionally, 3-methyladenine (3-MA), an inhibitor of autophagy, was applied in CS-exposed WT mice. The lung tissues and serum from patients and murine models were tested for FSTL1 and autophagy-associated protein expression by ELISA, western blotting and immunohistochemical. Autophagosome were observed using electron microscope technology. LTB4, IL-8 and TNF-α in bronchoalveolar lavage fluid of mice were examined using ELISA. Airway remodeling and lung function were also assessed. Results Both FSTL1 and autophagy biomarkers increased in COPD patients and CS-exposed WT mice. Autophagy activation was upregulated in CS-exposed mice accompanied by airway remodeling and airway inflammation. FSTL1± mice showed a lower level of CS-induced autophagy compared with the control mice. FSTL1± mice can also resist CS-induced inflammatory response, airway remodeling and impaired lung function. CS-exposed WT mice with 3-MA pretreatment have a similar manifestation with CS-exposed FSTL1± mice. Conclusions FSTL1 promotes CS-induced COPD by modulating autophagy, therefore targeting FSTL1 and autophagy may shed light on treating cigarette smoke-induced COPD.


2021 ◽  
Author(s):  
Simone Morris ◽  
Kathryn Wright ◽  
Vamshikrishna Malyla ◽  
Warwick J Britton ◽  
Philip M Hansbro ◽  
...  

AbstractCigarette smoke (CS)-induced inflammation leads to a range of diseases including chronic obstructive pulmonary disease and cancer. Environmental factors including gut microbiota make up are major modifying factors that determine the severity of cigarette smoke-induced pathology. Adult zebrafish display increased inflammatory cytokine transcription when exposed to cigarette smoke extract (CSE) but incongruously do not produce a mucosal leukocytic inflammation phenotype. Zebrafish embryos and larvae have been used to model the effects of cigarette smoking on a range of physiological processes and offer an amenable platform for screening modifiers of cigarette smoke-induced pathologies. Here we exposed zebrafish larvae to CSE and showed that it was toxic and we characterised a CSE-induced leukocytic inflammatory phenotype with increased neutrophilic and macrophage responses. The CSE-induced phenotype was exacerbated by co-exposure to microbiota from the faeces of CS-exposed mice, but not control mice. Microbiota could be recovered from the gut of zebrafish and studied in isolation. This demonstrates the utility of the zebrafish-CSE exposure platform for identifying environmental modifiers of cigarette smoking-associated pathology and demonstrates that the CS-exposed mouse gut microbiota potentiates the inflammatory effects of CSE across host species.


2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Jifeng Liu ◽  
Xiaoning Zhong ◽  
Zhiyi He ◽  
Jianquan Zhang ◽  
Jing Bai ◽  
...  

Cigarette smoke is a major effector of chronic obstructive pulmonary disease (COPD), and Th17 cells and dendritic cells (DCs) involve in the pathogenesis of COPD. Previous studies have demonstrated the anti-inflammatory effects of macrolides. However, the effects of macrolides on the cigarette smoke extract- (CSE-) induced immune response are unclear. Accordingly, in this study, we evaluated the effects of erythromycin (EM) on CSE-exposed DCs polarizing naïve CD4+ T cells into Th17 cells. DCs were generated from bone marrow-derived mononuclear cells isolated from male BALB/c mice and divided into five groups: control DC group, CSE-exposed DC group, CD40-antibody-blocked CSE-exposed DC group, and EM-treated CSE-exposed DC group. The function of polarizing CD4+ T cells into Th17 cells induced by all four groups of DCs was assayed based on the mixed lymphocyte reaction (MLR) of naïve CD4+ T cells. CD40 expression in DCs in the CSE-exposed group increased significantly compared with that in the control group (P<0.05). The Th17 cells in the CSE-exposed DC/MLR group increased significantly compared with those in the control DC/MLR group (P<0.05). Moreover, Th17 cells in the CD40-blocked CSE-exposed DC/MLR group and EM-treated CSE-exposed DC/MLR group were reduced compared with those in the CSE-exposed DC/MLR group (P<0.05). Thus, these findings suggested that EM suppressed the CSE-exposed DC-mediated polarization of CD4+ T cells into Th17 cells and that this effect may be mediated through inhibition of the CD40/CD40L pathway.


2013 ◽  
Vol 305 (8) ◽  
pp. L530-L541 ◽  
Author(s):  
Andras Rab ◽  
Steven M. Rowe ◽  
S. Vamsee Raju ◽  
Zsuzsa Bebok ◽  
Sadis Matalon ◽  
...  

Chronic obstructive pulmonary disease (COPD) is a progressive respiratory disorder consisting of chronic bronchitis and/or emphysema. COPD patients suffer from chronic infections and display exaggerated inflammatory responses and a progressive decline in respiratory function. The respiratory symptoms of COPD are similar to those seen in cystic fibrosis (CF), although the molecular basis of the two disorders differs. CF is a genetic disease caused by mutations in the cystic fibrosis transmembrane conductance regulator ( CFTR) gene encoding a chloride and bicarbonate channel (CFTR), leading to CFTR dysfunction. The majority of COPD cases result from chronic oxidative insults such as cigarette smoke. Interestingly, environmental stresses including cigarette smoke, hypoxia, and chronic inflammation have also been implicated in reduced CFTR function, and this suggests a common mechanism that may contribute to both the CF and COPD. Therefore, improving CFTR function may offer an excellent opportunity for the development of a common treatment for CF and COPD. In this article, we review what is known about the CF respiratory phenotype and discuss how diminished CFTR expression-associated ion transport defects may contribute to some of the pathological changes seen in COPD.


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